#pennedpossibilities 616 — Name a bizarre and hyper-specific detail that you know about one of your characters but is completely irrelevant to the story.
Zaphod's prom date.
This is something he doesn't know, in any of the versions of him that I've used.
The exact story varies depending on which version it is, but his prom date wasn't human, it was an alien being known as a Mimaran.
In Leland's segment of the cosmos, the various alien species are not yet widely known to exist at all. There are some people that know, including Leland, but there's some concerns among the galactic residents that earth regaining a strong magical field could be a detriment. They want time to reestablish their technologies that are based around the magical field before contacting earth on a broad level.
The Mimarans are single celled organisms. But the structures of their cells allow them to mimic anything roughly the same mass as them. They can do so to such a fine degree that it takes technology earth doesn't have yet, or magic to discover, and they have tricks around those. They can copy anyone they can get a genetic sample of, it isn't just looking like a random human.
So, this Mimaran was one of their scouts, sent to do another survey of earth to see how things were progressing.
It became she, and went to school in the same place as Zaphod. Zaphod being Zaphod took interest in a *gorgeous* new student, and they dated. The Mimaran was interested in current human social structures, so went along with it. Even to the point of designing a dress to "grow" as part of her form.
They danced, they had a great time, they went to Zaphod's home and Zaphod had sex for the first time. Mimarans do not reproduce that way, though they can reproduce sexually; it's just more of two Mimarans budding off part of themselves and combining it with the bud of another.
The next morning, Elizabeth was gone. Nobody saw her again. Zaphod was a bit upset, and filed a missing persons report, but nothing was ever discovered.
"Elizabeth" returned home, with her bolus of human genetic material that Zaphod had so happily given her. Having enjoyed his company, she set about mingling those genetics with a bud of her own.
Thus, there is a Mimaran child that, while not even part human in any real sense, is still Zaphod's only offspring. It can look exactly like him, and often behaves in similar ways, delighting its/his parent.
This child, and its parent, have returned to earth multiple times to see concerts by Zaphod's band, but have never contacted him, nor are they ever likely to.